The present invention relates to a side member for a heat exchanger, and more particularly to such a side member which can alleviate problems caused by expansion. The invention also relates to a heat exchanger incorporating such a side member.
Heat exchangers, such as radiators and condensers, conventionally consist of plural tubes extending between two tanks each for coolant or refrigerant or two headers (each associated with a tank) with fins (also called separators) disposed between the tubes. Usually, there are also two end fins to cover the exposed surface of the two end tubes. To protect the end fins and to provide structural support and rigidity to the entire unit, two support members (referred to hereinafter as side plates or side members), one on each end, extend between the headers or the tanks, as the case may be. These two side plates then form part of the outer periphery of the heat exchanger.
In use, hot fluid passes through the tubes and a passage of air over the tubes and the fins reduces the temperature of the fluid. However, since the overall temperature of the tubes is relatively high, the tubes thermally expand by a substantial amount with respect to their length when cold.
U.S. Pat. No. 3,939,908 relates to a radiator in which the problem caused by expansion of the tubes and a lesser degree of expansion of the side plates of the radiator is mitigated, by an expansion joint system.
The present assignees have provided a first solution to the problem of thermal expansion, which can lead to high stress in the tubes, or in the joint between the tube and the tank or header, by cutting the side plate of the heat exchanger which thereby allows the tubes to expand. This technique has however proved problematic. Firstly, cutting the side plate after brazing the tubes to the tank creates an additional operation which increases the cost of the heat exchanger. Cutting the plate is liable to increase the likelihood of the tubes being damaged, which causes wastage. Cutting the side plate also greatly reduces the structural integrity of the heat exchanger which can lead to damage during shipping, handling and installation.
It is therefore an object of the present invention to at least partially mitigate the above-mentioned difficulties.
According to a first aspect of the present invention there is provided a side member for a heat exchanger, the side member having a portion adapted to break under relatively low tension.
According to a second aspect of the present invention there is provided a side member for a heat exchanger having a first and a second header or tank, the side member having a first portion for extending from the first header/tank towards the second header/tank, a second portion for extending from the second header/tank towards the first header/tank, and a third portion disposed between the first and second portions, wherein the structural integrity of the third portion is substantially less than that of the first and the second portions.
According to a third aspect of the present invention there is provided a side member for a heat exchanger comprising a channel-shaped member having a base wall and two opposing side walls depending from the base wall, the side member having a portion wherein the side walls are interrupted and the base wall includes a region of weakness.
According to a fourth aspect of the present invention there is provided a side plate for a heat exchanger comprising a channel-shaped member having a base wall and two opposing side walls depending from the base wall, the side member having a portion wherein the base wall is interrupted and the side walls include a region of weakness.
Preferably the portion adapted to break under low tension includes a sharp fold in the side member.
Preferably the region of reduced structural integrity is provided by a sharp fold region in the side member.
Advantageously the region of weakness of the base wall comprises a sharp fold region in the base wall.
Preferably the base wall is scored in said sharp fold region.
According to a further aspect of the present invention there is provided a heat exchanger having a first and a second header or tank, plural tubes extending between the first and second header/tanks and at least one side plate extending alongside the tubes to connect together the first and second header/tanks, the side plate having a first portion extending from the first header/tank towards the second header/tank, a second portion extending from the second header/tank towards the first header/tank and a third portion disposed between the first and second portions, wherein the structural integrity of the third portion is substantially less than that of the first and second portions.
Advantageously the side plate comprises a channel-shaped member having a base wall and two opposing side walls depending from the base wall, the third portion of the side plate comprising a region wherein the side walls are interrupted and the base wall includes a region of weakness.
Alternatively the side plate may comprise a channel-shaped member having a base wall and two opposing side walls depending from the base wall, and the third portion of the side plate has a region wherein the base wall is interrupted and the side walls include a region of weakness.